"Broken pipe" during rsync, tunneled over ssh: Help!

[RD Egeland <rde lists oxsyn com>]

I'm running rsync tunneled over ssh in a cron job (the error also occurs if 
run manually) to send nightly backup files to a remote server, and I've got 
troublesome problems with either rsync or ssh.  Has anyone had similar errors?

The rsync command in my cron job is:
rsync -e ssh -avz /mnt/claws/backups/mail/mail\ foo com-`date +%A`.tar.gz 
foo bar ac uk:~/backups/foo/

Uploading machine (.com):
RH 7.3 with
openssh-3.5p1-1 (I upgraded)
rsync-2.5.4-2

Downloading machine (.ac.uk):
RH 8.0 with
openssh-3.4p1-2
rsync-2.5.5-1

Error which comes out quite regularly (usually less than 10M into the 
upload, but sometimes not at all):
rsync: error writing 9 unbuffered bytes - exiting: Broken pipe
rsync error: error in rsync protocol data stream (code 12) at io.c(464)


Greek to me.  At first, I assumed this was due to intermittent connectivity 
(I am using a cable modem and D-Link firewall router on one side), but the 
connection (amazingly) is quite rock-solid.  I've read about bugs in ssh, 
and notably, I notice that ssh connections to the 7.3 machine are dropped 
occasionally, sometimes with "bad network packet size" (or something like 
that).

So I believe this could be due to SSH problems.  But before I upgrade SSH 
using the sources, I figure I'd ask if anyone has been through this before.

Ryan